The right way for pigeons to follow their nose home

Pigeons are famous for navigating long distances of unfamiliar territory to find their way home. Recent studies suggest they're led by the nose - and now, researchers have confirmed that it's the right nostril that does all the work.

Biologist Anna Gagliardo of the University of Pisa in Italy and her collaborators have previously shown that pigeons may rely on odours carried on the wind - and not the Earth's magnetic field - to find their way home.

Now Gagliardo's team has discovered that the two nostrils are not equally useful. They crammed a rubbery paste into the left nostril of ten homing pigeons, and similarly bunged up the right nostril of another nine birds.

Then they strapped a miniature GPS data
logger to the back of each bird and released them, some 40 kilometres from home. The GPS trackers revealed that only if the right nostril was blocked do the pigeons lose their sense of direction. These birds stopped and explored more than normal birds, and they took more tortuous paths back home. Pigeons with an obstructed left nostril navigated normally.

Gagliardo's team already had some evidence that young birds rely on their right nostril to fly in the right direction - but this is the first evidence that experienced pigeons need a clear right nostril to find the quickest way home.

The researchers don't know exactly why the right side of the nose predominates when it comes to homing but they suggest that it's because birds favour their right nostril for recognising odours that they can link to locations in the world. This type of asymmetry in the use of body parts occurs in a variety of tasks and animals.